STUDIES OF ADHESION OF METAL PARTICLES TO SILICA PARTICLES BASED ON ZETA POTENTIAL MEASUREMENTS

The zeta-potentials of silica, copper, platinum and gold particles have been measured as a function of pH. The isoelectric points were found to be at pH 3.0, 5.8, 3.0 and 3.5, respectively. In the pH range 3.0 to 5.8 copper and silica particles are oppositely charged and accordingly the coating of silica with copper particles could be demonstrated. In the case of gold and platinum the sign of the charge is such that direct adhesion to silica particles cannot be expected and this was also demonstrated in the case of platinum.     

<Emphasis Type="Italic">N</Emphasis>-arachidonoyl glycine,an abundant endogenous lipid,potently drives directed cellular migration through GPR18, the putative abnormal cannabidiol receptor

Background  

Microglia provide continuous immune surveillance of the CNS and upon activation rapidly change phenotype to express receptors that respond to chemoattractants during CNS damage or infection. These activated microglia undergo directed migration towards affected tissue. Importantly, the molecular species of chemoattractant encountered determines if microglia respond with pro- or anti-inflammatory behaviour, yet the signaling molecules that trigger migration remain poorly understood. The endogenous cannabinoid system regulates microglial migration via CB₂ receptors and an as yet unidentified GPCR termed the 'abnormal cannabidiol' (Abn-CBD) receptor. Abn-CBD is a synthetic isomer of the phytocannabinoid cannabidiol (CBD) and is inactive at CB₁ or CB₂ receptors, but functions as a selective agonist at this G_i/o-coupled GPCR. N-arachidonoyl glycine (NAGly) is an endogenous metabolite of the endocannabinoid anandamide and acts as an efficacious agonist at GPR18. Here, we investigate the relationship between NAGly, Abn-CBD, the unidentified 'Abn-CBD' receptor, GPR18, and BV-2 microglial migration.     

Acid promoted cinnamyl ion mobility within peptide derived macrocycles

We are developing methods that restrict the conformational mobility of peptides and related heteropolymers while simultaneously altering their properties. Our experiments occur as processes wherein a conserved, lipophilic reagent is activated in stages to form composite products with unprotected polyamides in parallel. For each starting oligomer, the goal is to create not one, but rather a collection of products. The intent is for those materials to retain molecular recognition elements of the biopolymer, yet display that functionality as part of stable, cyclic structures having defined shapes and enhanced membrane solubility/permeability. Here we describe reagent 2 and its two-step integration into peptides to afford macrocyclic ethers (e.g., 4 when starting with W-W-Y). When those materials are treated with protic acid in anhydrous solvent, the cinnamyl unit migrates from the oxygen of tyrosine to distribute throughout the structure, forming new products via carbon/carbon bonding. These changes occur concomitantly with acid-promoted rearrangements/cyclizations of the dienyne appendage to generate mixtures containing unique macrocycles such as 15. Similar amalgamations of 2 with more diverse peptides is a means to begin accessing complex peptidomimetics systematically. From a library of screening fractions generated in this way, we have identified a small molecule that selectively promotes hippocampal neurogenesis in the adult mouse brain.     

Set the controls for the heart of the Sun

In this paper we describe experiments conducted with high-power lasers that are attempting to replicate, for a very short time and in miniature, conditions found in the Sun. Experiments to date have reached conditions in the outer part of the Sun. To reach the Sun's centre requires compression of material to very much greater than solid density and heating to over ten million degrees. To achieve this, a new class of experiments and a new generation of high-power lasers are required.     

Endolaryngeal changes during high-intensity phonation videolaryngoscopic observations

Using a five-part vocal figure and standard fiberoptic techniques, we have analyzed the laryngeal functions of a group of professional singers and have made five observations occurring during high-intensity phonation that contradict the accepted physiologic functioning of the larynx. We have analyzed these contradictions as they relate to the three endolaryngeal sphincters; this was accomplished by the development of a four-component vocal protocol to examine the changes in these laryngeal structures and the degree of independent control of each of these structures possible in this group of specialized subjects. We have attempted to explain our findings based on available data relating to the functions of the intrinsic and extrinsic laryngeal musculature (including the cricothyroideus muscle) and the neurologic mechanisms involved. Finally, we discuss this data as it relates to current vocal training.